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The Cost Of ATI Kernel Mode-Setting On Fedora 12

11-25-2009, 05:10 AM

Phoronix: The Cost Of ATI Kernel Mode-Setting On Fedora 12

One of the articles on Phoronix last week was entitled Intel Linux Graphics Shine With Fedora 12, which showed off the nice state of Intel graphics on this latest Red Hat release when it came to kernel mode-setting and its 3D stack with it working well "out of the box" and offering some nice performance gains over the earlier Fedora 10 and Fedora 11 releases. While the Intel stack may be improved in Constantine, the ATI support has taken a hit, as users were quick to point out in response to last week's article. In particular, when using the ATI kernel mode-setting driver in Fedora 12 (which is the default for pre-R600 hardware), there is a large performance discrepancy compared to using the traditional user-space mode-setting for ATI Radeon hardware. Today we are looking at what exactly the performance cost is for using ATI KMS in this new release.

Comment

Am I the only one who noticed the first graph maximum to be dangerously close to 33%, that is 1 out of the three cores? I don't know what you used for decoding, but libav is single threaded for the most part... To me it looks like with KMS it played at a slower speed and stopped playing to early after the time the movie should have finished.
And of course I wonder why the performance for UT2004 does increase with the resolution with UMS.

Comment

Use latets packages F12 from koji and you see that lots of those issues are already fixed and they will end up as updates in time. KDE4.3.3 works now perfectly with kms on 4850 (kwin effects on) )) no more glitches also ut2k4 and nexuiz works great now. Just today updated latest xorg-x11-drv-ati package and got a nice performance bump.